Solid electrolyte fuel cell

Abstract

A solid electrolyte fuel cell has an air electrode, a fuel electrode and a solid electrolyte film disposed between the air electrode and the fuel electrode. The solid electrolyte film is formed of yttria-stabilized zirconia in which alumina is added, the concentration of the supplemented alumina at a surface layer section of the solid electrolyte film being larger than that at a center layer section of the solid electrolyte film.

What is claimed is:  
     
       1. A solid electrolyte fuel cell comprising: 
       an air electrode;  
       a fuel electrode; and  
       a solid electrolyte film having a pair of opposed surfaces disposed between the air electrode and the fuel electrode,  
       wherein the solid electrolyte film is an alumina-containing yttria-stabilized zirconia in which the concentration of the alumina at the opposed surfaces of the solid electrolyte film is larger than the concentration of alumina in the center of the solid electrolyte film between those opposed surfaces.  
     
     
       2. A solid electrolyte fuel cell according to claim  1  wherein the solid electrolyte film comprises three juxtaposed layers and the concentration of alumina in the center member of said layers is less than that in the outermost members of said layers. 
     
     
       3. A solid electrolyte fuel cell according to claim  2  having a separator connected to each electrode and a charge collector connected to each separator. 
     
     
       4. A solid electrolyte fuel cell according to claim  3  in which the air electrode and charge collector associated therewith comprise lanthanum manganite, the fuel electrode comprises Ni-containing yttria-stabilized zirconia, and the separators comprise lanthanum chromite. 
     
     
       5. A solid electrolyte fuel cell according to claim  4  in which the center member of the electrolyte contains about 10% alumina and the outermost members of said layers comprise about 12-20% alumina. 
     
     
       6. A solid electrolyte film having a pair of opposed surfaces and comprising three juxtaposed layers of alumina-containing yttria-stabilized zirconia, wherein the concentration of alumina at said opposed surfaces is larger than the concentration of aluminum in the center of the three layers between said opposed surfaces and wherein the outermost members of said three layers comprise about 12-20% alumina and the layer between said outermost members contains about 10% alumina.